Concrete form u-clamp



1959 s. HOLMBOE, SR 2,868,250

CONCRETE FORM U-CLAMP Filed March 9, 1955 2 Sheets-Sheet 1 IN V EN TOR.

M 5 Min 3.

Jan. 13, 1959 L. s. HOLMBOE, SR 2,868,250

CONCRETE FORM U-CLAMP Filed March 9, 1955 2 Sheets-Sheet 2 [0336000604] [:1 ooooooooooooo j G 9 WIIIIIIIIIIIIIIIIIIIIIIII I 5 INVENTOR.

United States l atent CONCRETE FURM U-CLAMP Lawrence S. Holmboe, Sn, (llrlahoma fity, Gina.

Application March 9, 1955, Serial No. 493,243 4 Claims. or. 144-291 The present invention relates to the construction industry and more particularly to a clamping device for holding concrete forms and the like.

It is common practice in building construction, to erect a wooden form to be later filled with concrete which is allowed to harden therein, thus forming columns, beams, walls, curbs and the like. It is also conventional to reinforce these wooden forms with lengths of wooden bracing to maintain the desired shape and line of the form against the weight of the wet concrete. The bracing of these forms is costly, both from a labor or time element, and from the amount of lumber necessary to properly brace the forms. Furthermore the bracing is quite often destroyed, or partially so, when the forms are removed from the concrete therefore quickly terminating their useful life.

One of the prerequisites of concrete form construction for walls, beams, columns, curbs and the like, is that the bracing be sufliciently strong to maintain the Walls of the forms in rigid right angular or parallel relation.

Therefore a clamping device which may be used to grip opposing walls of a concrete form is highly desirable.

One clamping device for holding wall forms was made and is commonly referred to as a J-clarnp. The principal objection to this clamp is that no provision is included in the clamp construction to assist in maintaining a right angular relation between adjoining walls of the form. A further objection to this type of clamp is the manner in which the clamp is attached to form. The movable or adjustable clamping element of this clamp relied on a frictional gripping action with the body of the clamp to maintain the gripping action. This movable element is released from clamping position by a light blow of a hammer on the end of the element opposite the form gripping end. Therefore any accidental jar or blow on this end of the element renders the clamp useless until it has been properly replaced on the form.

It is therefore the primary object of this invention to 1 provide a clamping means for holding adjoining walls of .a concrete form in rigid right angular relation.

Another object of this invention is to provide a clamping device which will rigidly hold opposing walls of a concrete form in parallel relation.

An additional object of this'invention is to provide an adjustable clamping means for concrete forms which may be quickly and easily installed and when once installed will not accidentally become disengaged from the form.

Still another object of this invention is to provide an adjustable clamping means which is light in weight and yet is strong and durable.

A further object of this invention is to provide an adjustable device of this class which may be readily used on any concrete form such as curbings, beams, columns, walls or the like.

A still further object of this invention is to provide a device of this class which is relatively small in size and which may be repeatedly used without showing any appreciable wear.

assassin Another important object is to provide an adjustableclamping device of this class which has few moving parts and which are all so arranged relative to each other to prevent their getting out of order or inadvertently separated or lost.

The present invention accomplishes these and other objects by providing a clamping means which comprises: an elongated member having a rigid right angular extending clamping arm at one end; a movable clamping arm slidably carried by the member in substantially right angular relation thereto and in parallel co-operating gripping relation with the rigid arm thus forming a substantially U-shaped clamp. The elongated member is provided with a plurality of spaced-apart perforations throughout the end portion opposite the rigid arm. A substantially triangular shaped wedge having a transverse slot is slidably carried on the perforated end of the member by the slot in the wedge. The wedge acts to force the co-operating clamping armsinto gripping relation when forcibly driven between the movable arm and a pin removably carried by one of the perforations.

Other objects will be apparent from the following description when taken in conjunction with the accompanying two sheets of drawings, wherein:

Figure 1 is an elevational view of the clamping device, per se and showing, in dotted lines, the relative movement of associated parts;

Figure 2 is a perspective view of the gripping edge of the rigid clamping arm of the device;

Figure 3 is a vertical cross-sectional view taken substantially along line 3--3 of Fig. 2;

Figure 4 is a perspective view of the movable clamping arm of the device;

Figure 5 is a perspective view of the wedging element of the device;

Figure 6 is a vertical cross-sectional view taken substantially along line 6-6 of Fig. 5

Figure 7 is a fragmentary elevational view illustrating the serrations along the gripping edge of the clamping arms;

Figures 8, 9 and 10 are elevational views illustrating the device operatively installed on concrete forms for, a curbing or the like, a column, and a beam, respectively, the form structure thereof being shown in dotted lines; and,

Figure 11 is a vertical cross-sectional view taken substantially along line 1111 of Fig. 4.

Like characters of reference designate like parts in those figures of the drawings in which they occur.

The reference numeral 15 indicates the device, as a whole, which is substantially U-shaped in general configuration. The numeral 16 indicates a selected length of strap iron or other suitable material which is substantially rectangular in transverse cross-sectional area. A selected length of similar material is integrally connected at one end to one end 18 of the member 16 in right angular relation thereto forming arigid arm 20 lying in substantially the same plane with relation to the member 16. From a point intermediate to its ends to the outermost or free end 22 the member 16 is centrally provided with a longitudinally extending row of relatively closely spacedapart through perforations or aperatures 24 for the purposes more fully explained hereinbelow.

A substantially U-shaped gripping element 26, Fig. 2, which is of substantially equal length with relation to the rigid arm 20, is longitudinally placed with its legs 28 and 30 on opposing sides of the arm 20, Fig. l, forming a gripping edge or face 32 at right angle with relation to the member 16 and disposed toward the perforated end portion 22. The element 26 is rigidly connected to the arm 24} by rivets 34 through suitable co-operating bosses 36 formed on the free edges of the legs 28 and 30.

Patented Jan. 13, 1959 v The gripping edge 32 which forms the bight of. the U-shaped element 26 has a .central longitudinal ridge as indicated by the line 38 extending outwardly oppositely fromthe .legs. 2. 3; and Bill Thegripping edge 32 has opposingsides which are transversely tapered or beveled converging and meeting at the line 33 as clearly shown in the drawings. The edge 32 is further provided with a. plurality of transverselydisposed grooves or serrations 4d,. see Fig. .7, for the purposes more fully explained hereinbelow. The opposing edges of the gripping edge 32 are further provided with a plurality of spaced-apart bulges or enlarged areas .42 lying in the same plane with relation to the'sides of the gripping edge 32 and which are centrally perforated for the reasons which will be presently apparent.

Referring now. more particularly to Fig. 4, the referencenumeral 35 indicates, as a whole, a movable arm having. an; enlarged.substantially rectangular end portion $6 and an :integral gripping edge .or face 458 similarly formcdwith relation. to theedge '32 extending laterally from the portion l6'the edge 48 is substantially of equal. length with relation to theelement 26.. The free end of the edgev is rigidly. connected to the portion 46 by an angularly disposed. brace 50, A rectangular slot 52 is centrallycut throughthe longitudinallength of the end portion as, disposed atright angle with relation to the gripping edge 48. The size of the slot 52 is such that it closely receives the member 16 longitudinally therein (Fig.1) and maintainsthe gripping edges 32. and

d8 in parallel relation and lying in substantially the same plane. The edge .53 of the endportion 46 is formed concave (Fig. 11) throughout its length and is disposed transverselvof the member 16 and substantially parallel with relation to the grippingedge 32.

Referring now to Fig. 5 the numeral 54 indicates, as a whole, a substantially triangular shaped wedge, rigidly reinforced as shown in the drawings; The wedge 54 has one longitudinal side 56 which is convex as shown in Fig. 6 and is disposed parallelwith the edge 58 of the movable arm. The purpose of the convex edge-.56 is to mate with or be nested by the concave edge 58. The concavity of the edge 58 acts to prevent the wedge from spreading or increasing the depth of the slot 68, as seen in Fig. 5, when thewedge'is forcibly moved as more fully explained-hereinbelow. The wedge 54 has a tapered side s0 opposite the side 56 extending from a point adjacent the end 62 to the apex 64 of the triangular shape. The end 66 of the wedge is substantially truncated rectangular pyramidally shaped. forreceiving hammer blows on the truncated end portion thus preventing fracture of. the wedge and for. the purposes which will presently be apparent. The wedge is longitudinally centrally through, slotted transversely intermediate its ends as at 68. The vertical .depth ofthe slot 68, as seen in Pig. 5, is such that it freely receives the member 16 therein. A flexible element such as a length of chain 'lll is rigidly connected to the upper surface, as seen in Fig. 5, of the wedge. The opposite or free end of the chain 70 is rigidly connected to one end of a cylindrical pin 72. Diametrically the pin 72 is slightly smaller than t the perforations 24 which frictionally and removably receivethe pin. The pin is preferably slightly longer than the vertical thickness of the wedge, as seen in Fig. 5, a rivet 73 adjacent the end 22 of the member 16 prevents removal of the wedge 54 therefrom. Obviously the wedge 54 may be reversed from the position shown in Fig. l, disposing the end 66 toward the free end of the arm 45.

Operation In operation the device is placed on concrete form walls 86) and 81 (Fig. 8) with the rigid arm adjacent the wall and the member 16 resting on the top of the walls 30 and 81. The movable arm is longitudinally slid along the member 16 until the edge d8 contacts the outer side of the wall 81 opposite the wall 80. The wedge 54 is manually positionedadjacent the...

edge 5'8 of the arm 45 with the end 66 laterally disposed away from the member 16. The pin 72 is then inserted into the perforation nearest the edge 68 of the wedge. hereafter the wedge is driven longitudinally across the transverse width of the member 16 by blows of a hammer on the end 66. It seems obvious that this action will frictionally engage the tapered edge 68 with the pin 72 and move the wedge 54 and the movable arm 45 longitudinally of the member 16 as shown by dotted lines (Fig. l) and thus grip the form between the edges 32 and Furthermore it seems obvious that the edges 32 and dil being parallel and in right angular relation with respect to the member 16 that they will'hold the sides or walls fill and fill of the form in parallel relation. In driving the wedge 54 the gripping edges 32 and 4-3 first contact the Wood forms in point contact, that is, the tip only of the gripping edge, as indicatedby the line 33, contacts the form, further pressure onthe wedge;

causes the edges 32 and 43 to start. entering the surface of the wood effecting a line contact with the form. Additional pressure on the wedge brings the entire serrated gripping edges into contact with theform wall,

effecting a full race contact firmly gripping the form to prevent slippage of the clamp. The clamp 15 may be further rigidly positioned on the form walls by inserting small nails, not shown, through the perforations in the bulges 4 2. The device may be easily removed from the form by a light tap of a hammer on the end 62 of the wedge and by removing any nails used on the gripping ed .es.

iig. 9 illustrates a. pair. of the clamping devices 15 installed on. the walls 82 and 83 of a column in a similar manner as disclosed bereinabove. It seems obvious that two of the devices installed in this manner will insure maintaining the walls of the column in light angular relationship.

in Fig. 10 is illustrated the adaptability of the device to the form walls 85 and 86 of a beam. The upper edges of the form walls 85 and lit; are rigidly held in place by a pair of purlins 87 and 88, respectively. Thus the device 15 installed on the lowerends of the form walls 35 and 86 in a similar manner. as disclosed hereinabove will hold the lower ends of Walls .of the beam form in rigid parallel relation.

Obviously the invention is susceptible .to changes or alterations without defeatingv its practicability, and .I

therefore do not wish to be confined vto the preferred embodiment shown in the drawings and described herein, further than i am limited by the scope of the appended claims.

I claim:

1. A concrete form U-clarnp, including: an elongated flat bar member having a rigid right angular extending arm permanently secured at. one end thereof in the plane of the width of the bar, said member having a plurality of longitudinally spaced-apart perforations normal to the said plane and adjacent the end opposite said rigid arm, said arm having a longitudinally ridged and transversely serrated gripping face extending along the longitudinal edge facing said opposite end; a movable arm slidably carried by said member in parallel relationwith said rigid arm, said movable arm having a gripping face similar to and for cooperatively gripping a concrete form with said carried by one of said perforations adjacent and between said wedge and said opposite end, whereby transverse movement of said Wedge in the plane of saidbar urges said movable arm toward said rigid arm to grip opposing walls of a concrete form therebetween.

2. A concrete form U-clamp, including: an elongated flat bar member having a rigid right angular extending arm permanently secured at one end thereof in the plane of the width of the bar, said member having a plurality of longitudinally spaced-apart perforations normal to said plane and adjacent the end opposite said rigid arm, said arm having a serrated gripping face extending along the longitudinal edge facing said opposite end, a movable arm slidably carried by said member and having a serrated gripping face in parallel relation with said rigid arm for cooperatively gripping opposite sides of a concrete form, the end of said movable arm opposite said serrated edge being substantially normal to the axis of said bar member and having a concave edge disposed transversely thereof; a Wedge longitudinally slotted to be longitudinally and transversely slidably carried by said member, said wedge having one longitudinal convex edge through which the slot passes disposed adjacent to and interfitting with said concave edge of said movable arm; and a pin removably carried by one of said perforations adjacent said wedge opposite said convex edge, whereby forced transverse movement of said wedge relative to said member urges said movable arm toward said rigid arm to grip opposing walls of a concrete form therebetween and said interfitting concave and convex surfaces prevents spreading of the slot walls.

3. The U-clamp as defined in claim 2 in which each of the opposing serrated gripping faces of'said arms is composed of transversely grooved surfaces meeting in a ridge extending longitudinally of the face to thus achieve initial line contact with the opposing form walls.

4. A concrete form U-elamp, including: an elongated member having a rigid right angularly extending arm at one end, said member and said arm lying in the same plane, the end portion of said member opposite said rigid arm having a plurality of centrally disposed longitudinally spaced-apart perforations, the longitudinal edge of said arm disposed toward said perforations having opposing outwardly converging transversely serrated surfaces forming an obtuse wedge-like gripping face; an elongated movable arm having a transverse slot adjacent one end for slidably mounting said movable arm on said member in co-operative parallel relation with said rigid arm, said slotted end of said movable arm having a concave edge disposed transversely of and toward said perforated end of said member, one longitudinal edge of said movable arm having opposing outwardly converging transversely serrated surfaces forming an obtuse wedge-like gripping face parallel with the gripping face of said rigid arm; an elongated substantially triangular shaped wedge having a transverse longitudinally extending through slot for slidably mounting said wedge on said member, said triangular wedge having a convex base side slidably disposed adjacent said concave edge of said movable arm, said triangular wedge having one truncated rectangular pyramidal shaped driving end; a pin removably carried by one of said perforations adjacent said wedge opposite said convex edge, whereby force progressively applied to said pyramidal end moves said Wedge transversely of said member and urges said movable arm toward said rigid arm for effecting multi-point line and subsequently face contact of said gripping faces on opposing walls of a concrete form therebetween; and flexible means connecting said pin with said wedge.

References Cited in the file of this patent UNITED STATES PATENTS 1,082,112 Cutler Dec. 23, 1913 1,308,084 Lampert July 1, 1919 1,433,830 Lampert Oct. 31, 1922 1,501,212 Fronsoe et al. July 15, 1924 1,552,912 Colt Sept. 8, 1925 1,682,740 Colt Sept. 4, 1928 1,726,542 Colt Sept. 3, 1929 2,069,085 Day Jan. 26, 1937 2,513,882 Magdiel et a1. July 4, 1950 FOREIGN PATENTS 742,281 France Mar. 3, 1933 861,378 Germany Dec. 29, 1952 

